Guest speaker - Tuberculosis Flashcards
How many tuberculosis patients die worldwide?
every 22 seconds
what are the microbiological characteristics of tuberculosis?
Aerobic (need oxygen), non-spore forming, non-motile bacillus (obligate intracellular pathogen)
How does tuberculosis grow?
Generation time 20-24 hours, buff-colored, rough, friable colonies
If it grows slow its hard to get drugs into pathogens and kill it
What does tuberculosis look like under a microscope?
Pink staining (acid fast) with ziehl-neelson, orange-yellow fluorescence with auramine-rhodamine
How is tuberculosis transmitted
- Airborne droplet nuclei
- Suspended for hours
- Viable for hours out of sun
- 1 or 2 mycobacterium tuberculosis enough to infect a normal person
~30% of heavily exposed, non HIV pts get infected
Average of 10-15 people infected per year from an untreated case
What are the two types of tuberculosis and why are they different?
Latent TB infection
- no symptoms
- not infectious
- can reactivate to disease
- HIV matters (50% vs 5%)
Active TB disease
- have symptoms
- infectious
- cured with treatment
- risk of death
Infection vs disease of tuberculosis stats
latent TB infection –> 5% chance will get active TB disease with no HIV
latent TB infection –> 50% chance they will contract HIV and TB disease
70% of untreated TB patients die and 5% relapse
infected aerosol TB –> 5% disease active TB disease
infected with aerosol TB –> 95% chance of latent TB infection
Tuberculosis Epidemiology
In the 16th and 17th century TB caused 20-30% of all deaths worldwide
Tuberculosis in the US
Tuberculosis was reduced 4% in the US and if it gets reduced 4% every year then by 2100 it will be eliminated
over 70% of US TB cases are from non-US born
San Diego also have 3x higher amounts of TB cases than in the US
COVID is making TB cases rise again since it took a nosedive in 2019
Why did COVID make TB cases go down?
16-41% decline in TB diagnosis and treatment worldwide in 2020
Some likely due to reduced transmission due to lockdowns
Most was due to reduced diagnosis as public health teams shifted attention to covid-19
Modeling estimates an additional ~1.4 million TB deaths over next 5 years
How is TB diagnosed
In 1918 it was done by microscopy and in 2019 it is still mostly done by that and now there are drug resistant TB that has high mortality
TB infection is done by immune response, blood testing
disease is done by CXR or molecular diagnostics
True or false? San Diego has a lower incidence of tuberculosis than the rest of the US?
False, it has 3x higher and this is because it is right next to the boarder
what are the two primary phases of tuberculosis infection?
Latent TB infection and it is not infectious
Active TB disease and it is infectious
the main reason it is so challenging to diagnose tuberculosis active infection is because the bacteria are so
bacteria is hard to grow, it is a very slow process
True or false? most people infected with tuberculosis do not have symptoms
true
